Testicular time bomb: Older dads’ mutant sperm

The clock is always ticking for testicles (Image&colon; Emiliano Ponzi)

Every man’s sperm is fighting an evolutionary civil war – and over the years, it ups the risk of fathering a child with a genetic disorder

“I THOUGHT, ‘Oh my god, I have mixed all the samples, I have made a massive mistake here’. And I tore my hair overnight.” It was 2003, and Anne Goriely had just seen the results of a series of tests on sperm samples. She was looking at them to try to solve the riddle of a rare developmental disorder called Apert syndrome. At first sight, she thought that there had been some kind of contamination or mix-up.

But as Goriely tried to work out what had gone wrong, another explanation sprang to mind. “It just clicked&colon; ‘Maybe there is no contamination, maybe these are real ...

To continue reading this article, log in or subscribe to New Scientist